From 277a1ae3879a82a15a2e2d6741e38e31ea6487ee Mon Sep 17 00:00:00 2001 From: Chunyan Zhang Date: Thu, 13 Nov 2025 15:28:01 +0800 Subject: mm: softdirty: add pgtable_supports_soft_dirty() Patch series "mm: Add soft-dirty and uffd-wp support for RISC-V", v15. This patchset adds support for Svrsw60t59b [1] extension which is ratified now, also add soft dirty and userfaultfd write protect tracking for RISC-V. The patches 1 and 2 add macros to allow architectures to define their own checks if the soft-dirty / uffd_wp PTE bits are available, in other words for RISC-V, the Svrsw60t59b extension is supported on which device the kernel is running. Also patch1-2 are removing "ifdef CONFIG_MEM_SOFT_DIRTY" "ifdef CONFIG_HAVE_ARCH_USERFAULTFD_WP" and "ifdef CONFIG_PTE_MARKER_UFFD_WP" in favor of checks which if not overridden by the architecture, no change in behavior is expected. This patchset has been tested with kselftest mm suite in which soft-dirty, madv_populate, test_unmerge_uffd_wp, and uffd-unit-tests run and pass, and no regressions are observed in any of the other tests. This patch (of 6): Some platforms can customize the PTE PMD entry soft-dirty bit making it unavailable even if the architecture provides the resource. Add an API which architectures can define their specific implementations to detect if soft-dirty bit is available on which device the kernel is running. This patch is removing "ifdef CONFIG_MEM_SOFT_DIRTY" in favor of pgtable_supports_soft_dirty() checks that defaults to IS_ENABLED(CONFIG_MEM_SOFT_DIRTY), if not overridden by the architecture, no change in behavior is expected. We make sure to never set VM_SOFTDIRTY if !pgtable_supports_soft_dirty(), so we will never run into VM_SOFTDIRTY checks. [lorenzo.stoakes@oracle.com: fix VMA selftests] Link: https://lkml.kernel.org/r/dac6ddfe-773a-43d5-8f69-021b9ca4d24b@lucifer.local Link: https://lkml.kernel.org/r/20251113072806.795029-1-zhangchunyan@iscas.ac.cn Link: https://lkml.kernel.org/r/20251113072806.795029-2-zhangchunyan@iscas.ac.cn Link: https://github.com/riscv-non-isa/riscv-iommu/pull/543 [1] Signed-off-by: Chunyan Zhang Acked-by: David Hildenbrand Cc: Albert Ou Cc: Alexandre Ghiti Cc: Al Viro Cc: Arnd Bergmann Cc: Axel Rasmussen Cc: Christian Brauner Cc: Conor Dooley Cc: Deepak Gupta Cc: Jan Kara Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Xu Cc: Rob Herring Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Yuanchu Xie Cc: Alexandre Ghiti Cc: Andrew Jones Cc: Conor Dooley Signed-off-by: Andrew Morton --- fs/proc/task_mmu.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) (limited to 'fs/proc') diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 41b062ce6ad8..2b4ab5718ab5 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1584,8 +1584,6 @@ struct clear_refs_private { enum clear_refs_types type; }; -#ifdef CONFIG_MEM_SOFT_DIRTY - static inline bool pte_is_pinned(struct vm_area_struct *vma, unsigned long addr, pte_t pte) { struct folio *folio; @@ -1605,6 +1603,8 @@ static inline bool pte_is_pinned(struct vm_area_struct *vma, unsigned long addr, static inline void clear_soft_dirty(struct vm_area_struct *vma, unsigned long addr, pte_t *pte) { + if (!pgtable_supports_soft_dirty()) + return; /* * The soft-dirty tracker uses #PF-s to catch writes * to pages, so write-protect the pte as well. See the @@ -1630,19 +1630,16 @@ static inline void clear_soft_dirty(struct vm_area_struct *vma, set_pte_at(vma->vm_mm, addr, pte, ptent); } } -#else -static inline void clear_soft_dirty(struct vm_area_struct *vma, - unsigned long addr, pte_t *pte) -{ -} -#endif -#if defined(CONFIG_MEM_SOFT_DIRTY) && defined(CONFIG_TRANSPARENT_HUGEPAGE) +#if defined(CONFIG_TRANSPARENT_HUGEPAGE) static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmdp) { pmd_t old, pmd = *pmdp; + if (!pgtable_supports_soft_dirty()) + return; + if (pmd_present(pmd)) { /* See comment in change_huge_pmd() */ old = pmdp_invalidate(vma, addr, pmdp); -- cgit v1.2.3